Periodontal disease, a periodically active infection of the tissues that help anchor teeth, has supplanted tooth decay as the most common cause of tooth loss in adulthood. Statistics from a 1987 survey by the National Institute of Dental Research found that 24% of U.S. adults had periodontal disease, clearly pointing to the need for a more reliable means of detecting and monitoring this affliction. Intelligent Optical Systems (IOS) proposes to develop a low-cost, time- saving, fiber optic sensor technology that uses fluorogenic substrates to detect the proteases in gingivital crevicular fluid. In Phase I, we will explore the feasibility and reproducibility of testing and quantifying the activities of serine proteases, cystenyl proteases, and collagenases in vitro. IOS will custom-fabricate optical fibers into biosensor probes, and conduct mechanical and optical tests to verify their suitability for the proposed application. Simultaneous in vitro experiments on control samples and gingival crevicular fluid from healthy sites and from locations with gingivitis and periodontitis will establish a base for developing software for the automated determination of dental tissue health. These parallel efforts will be combined at the end of the project in a demonstration of the optical fiber periodontal microprobe. PROPOSED COMMERCIAL APPLICATION: The proposed technology for early detection and precise localization of periodontal disease activity will permit real-time measurement of periodontal disease, easy and rapid assessment of treatment response, improved diagnostic information presented clearly by means of a real-time graphic display, and automatic archiving and retrieval of patient data for tracking and comparison purposes, all with minimal or no patient discomfort. This will make it extremely attractive to dentists and periodontists throughout the developed world.